VAP-1 is an amine oxidase (semicarbazide sensitive amine oxidase, SSAO) which is abundant in human plasma (Non-Patent Document 1), and shows remarkably increased expression in vascular endothelium and vascular smooth muscle of the inflammatory region. While the physiological role of VAP-1 has not been clarified until recently, VAP-1 gene was cloned in 1998, and VAP-1 has been reported to be a membrane protein that regulates rolling and migration of lymphocytes and NK cells as an adhesion molecule under regulation of expression by inflammatory cytokines. Although the amine as a substrate is unknown, it is considered to be methylamine generated in any part of biological body. It is also known that hydrogen peroxide and aldehydes produced due to the amine oxidase activity in the molecule are important factors of adhesion activity.
A recent report has documented that the VAP-1 enzyme activity in plasma increases in patients with diabetes mellitus, whether type I or type II, and the increase is particularly remarkable in the patients with diabetes mellitus suffering from retinopathy complications (Non-Patent Documents 2 and 3).
In addition, it has been reported that VAP-1 is related to the following diseases:                (1) cirrhosis, essential stabilized hypertension, diabetes mellitus, and arthrosis (Patent Documents 1 and 2);        (2) endothelium damage (in diabetes mellitus, arteriosclerosis, and hypertension), cardiovascular diseases related to diabetes mellitus and uremia, pain related to gout and arthritis, and retinopathy (in diabetes mellitus patients) (Patent Document 3);        (3) (connective tissue) inflammatory diseases or conditions (rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and osteoarthritis or degenerative joint disease, Reiter's syndrome, Sjogren's syndrome, Behcet's syndrome, relapsing polychondritis, systemic lupus erythematosus, discoid lupus erythematosus, systemic sclerosis, eosinophilic fasciitis, polymyositis, dermatomyositis, polymyalgia rheumatica, vasculitis, temporal arteritis, polyarteritis nodosa, Wegener's granulomatosis, mixed connective tissue disease, and juvenile rheumatoid arthritis); gastrointestinal inflammatory diseases or conditions [Crohn's disease, ulcerative colitis, irritable bowel syndrome (spastic colon), fibrotic conditions of the liver, inflammation of the oral mucosa (stomatitis), and recurrent aphtous stomatitis]; central nervous system inflammatory diseases or conditions (multiple sclerosis, Alzheimer's disease, and ischemia-reperfusion injury related to ischemic stroke); pulmonary inflammatory diseases or conditions (asthma, adult respiratory distress syndrome, and chronic obstructive pulmonary disease); (chronic) skin inflammatory diseases or conditions (psoriasis, allergic lesions, lichen planus, pityriasis rosea, contact dermatitis, atopic dermatitis, and pityriasis rubra pilaris); diseases related to carbohydrate metabolism (diabetes mellitus and complications from diabetes mellitus) including microvascular and macrovascular diseases (arteriosclerosis, vascular retinopathies, retinopathy, nephropathy, nephrotic syndrome and neuropathy (polyneuropathy, mononeuropathies and autonomic neuropathy), foot ulcers, joint problems, and increased risk of infection); diseases related to aberrations in adipocyte differentiation or function or smooth muscle cell function (arteriosclerosis and obesity); vascular diseases [atheromatous arteriosclerosis, nonatheromatous arteriosclerosis, ischemic heart disease including myocardial infarction and peripheral arterial occlusion, Raynaud's disease and phenomenon, and thromboangiitis obliterans (Buerger's disease)]; chronic arthritis; inflammatory bowel diseases; and skin dermatoses (Patent Documents 4, 5, and 6, and Non-Patent Documents 4 and 5);        (4) diabetes mellitus (Patent Document 7);        (5) SSAO-mediated complications [diabetes mellitus (insulin dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM)) and vascular complications (heart attack, angina, strokes, amputations, blindness, and renal insufficiency)], and macular edema (for example, diabetic and non-diabetic macular edema) (Patent Documents 8 and 11); and        (6) hepatitis, transplantation, and the like.        
Under the present circumstances, a drug for treating or preventing the above diseases has been demanded.
Furthermore, Patent Document 9 discloses that a compound represented by the formula (A) has a VAP-1 inhibitory activity.

In addition, Patent Document 10 discloses that a compound represented by the formula (B) has a VAP-1 inhibitory activity.
